A systematic review and meta-analysis on abnormal posturing among brain injury patients

Background  Abnormal motor posturing (AMP), exhibiting as decorticate, decerebrate, or opisthotonos, is regularly noticed among children and adults. Objective  This systematic review and meta-analysis examined the risk factors and outcome of posturing among severe head and brain injury subjects. Methods  Based on the inclusion and exclusion criteria and using MeSH terms: “decerebrate posturing”, “opisthotonic posturing”, “brain injury”, and/or “cerebral injury” articles were searched on Scopus, PubMed, Science Direct, and google scholar databases. Observational studies, case series, and case reports were included. Results  A total of 1953 studies were retrieved initially, and based on the selection criteria, 20 studies were finally selected for review and were analyzed for meta-analysis based on the mortality between the hematomas. The functional outcomes of this study are the risk factors, mortality rate and Glasgow Outcome Scale. Decerebrative patients were higher among the studies related to head injury surgeries. Males were mainly treated for decerebrate postures compared with the female subjects. Extradural hematoma and acute subdural hematoma with cerebral contusion were quite common in the surgical mass lesions. Conclusion  The findings reported that the lesion types, the operative procedures, and the age of the decerebrating patients with brain injuries are the significant prognostic factors determining the survival outcomes.


INTRODUCTION
Abnormal motor posturing (AMP) includes decorticate and decerebrate postures response usually to noxious stimuli.The AMP is classified as decorticate and decerebrate postures in conventional movements of the trunk extension and edges with an increased muscular tone showing sign of brain injury. 1,2Subjects with cerebral malaria, seizures, and other acute encephalopathies are commonly studied and associated with AMP. 3 Supratentorial and infratentorial lesions may cause both postures and are involved marginally in brainstem injury. 4ecerebrate posturing might develop from brainstem lesions, whereas the decorticate posture regularly follows lesions at the cerebral cortex level. 5Compared with decerebrate posturing, decorticate posture more stereotypically requires an injury more rostral and is considered the red nucleus at the intercollicular level in the middle of the brain. 6ifferentiating extradural hematoma (EDH) from subdural hematoma (SDH) in the head is typically forthright.Compared with EDH, SDHs are more common and identifiable with distinguishing features. 7Intracerebral hemorrhage (ICH) in brain injury results in high morbidity and mortality. 8raumatic brain injury (TBI) is caused by a sudden, external, physical assault damages in the brain.A study estimated that each year, worldwide, there could be 69 million TBIs and 7.95% are considered as severe as the patients with a Glasgow Coma Scale (GCS) of 8 or less. 9The GCS is the most substantial factor in prognosticating outcomes in brain injury, and the most specific one is the motor response pattern. 10,11ter a head injury, decerebrate rigidity is an important prognostic indicator of brain stem damages or compression secondary to tentorial herniation.
The mortality rate could increase from 33% to 70% for severe head injury (GCS <8) when the patient indicates signs of decerebration. 2,12To achieve better results and avoid the conditions associated with high morbidity and mortality, prompt diagnosis, treatment, and proper management planning are needed.This study reviews the management and assessment of decorticate and decerebrate posturing among brain injury subjects and highlights the role of the prognosticators of outcomes of head and brain injury using meta-analysis.

Eligibility criteria
The literature searches were limited based on our inclusion and exclusion criteria.Intervention, case-control, case reports, case series, and cross-sectional studies dealing with brain injury and posturing were included.Studies with any one of the postures among head and brain injury subjects with no limits on age, gender, ethnicity, and regions were recruited.There were no limitations on the date of publication or the regions where the studies were performed.The participants in the study needed to have decerebrate or decorticate posture associated with a brain injury.Abstracts, reviews, animal studies, studies with insufficient protocol, and articles with required information missing were excluded from this study.In addition, the reference section from the included literature and relevant retrospective studies articles were also reviewed for additional relevant studies.

Data extraction
Two independent reviewers examined and extracted the data from the selected studies.Mortality and survival rate, Glasgow Outcome Scale (GOS), radiological findings, Glasgow Coma Scale (GCS), neurological manifestation, and operative procedures are the brain injury-related variables.All the data were recorded in Rayyan systematic review and Zotero for further analysis.

Statistical analysis
The pooled mortality rates of decerebrate patients between different types of intracranial hemorrhage (EDH, SDH, and ICH) were evaluated using odds ratio (OR) values and the corresponding 95% confidence intervals (CI).Rayyan systematic review and Zotero software were used for systematic review analysis.The effect of the model selected depends upon the level of heterogeneity (I 2 ).Heterogeneity between studies was analyzed using the I 2 statistic and Q-test, whereby p < 0.10 and I 2 > 50% indicates high heterogeneity, and a random-effect model was applied for meta-analysis.Publication bias was visually identified using funnel plots, and any asymmetric plot suggests a possible publication bias.All data analysis was performed using Review Manager ("Version 5.3.Copenhagen: The Nordic Cochrane Centre, the Cochrane Collaboration, 2014").The statistical significance was defined as a p-value of less than 0.05.We have assessed the risk of bias using the ROBINS-I in robvis tool (https://mcguinlu.shinyapps.io/robvis/).

Study selection
A total of 1953 articles were identified from the five literature databases.Among those, 444 duplicates were removed, and 150 articles were excluded based on the titles and abstracts.The leftover articles were screened and excluded based on the inclusion and exclusion criteria.Of 959 articles, 939 were excluded based on lack of information, irrelevant, animal studies, other languages, and review articles.Finally, the literature search from the five databases yielded 20 studies 5,14-32 until March 2022 (►Figure 1).The study characteristics of the selected studies are shown in ►Table 1.Out of 20 articles, most of the studies were from the United States (45%), followed by Germany (10%), India (10%), and South Korea (10%), and the least, among Italy (5%), Kenya (5%), Canada (5%), Brazil (5%), and South Africa (5%).Most of the studies were: Case reports (12; 60%), and the rest were prospective and retrospective studies (40%).

Clinical characteristics of the patients
Among the final retrieved articles, 1209 patients were assessed for this study.Based on the data available from the selected studies, most of them were males (286) compared with females (91).Those patients ranged between 3 to 86 years old.For most patients with any significant operable lesion, the Computed tomography (CT) scan was conducted in most of the studies for EDH, SDH, and cerebral contusions.Most studies have used craniotomies as the operative procedures to evacuate the routine trauma flaps for EDH, acute SDH, and cerebral contusions.After the surgery, steroids, mannitol, and intravenous solution were the common treatment given to the patients.Seizures, unilateral decerebrate rigidity, and decorticate rigidity are the common outcomes of the selected studies.

Mortality outcomes
Based on the GCS scores, the comparison of EDH, SDH, and ICH was analyzed based on the mortality rates by injury severity.Hence, only four 16,24,26,32 studies were included for meta-analysis.►Figure 2 shows a forest plot comparing the EDH and SDH groups.The results indicated that decerebrate patients with EDH have a greater mortality rate than SDH (pooled OR ¼ 0.18, 95% CI ¼ 0.07-0.50,p < 0.05).►Figure 3 shows a forest plot comparing the EDH and intracerebral hematoma (ICH) groups.No significant difference was noticed between the mortality rate of decerebrate patients with EDH compared with ICH (pooled OR ¼ 0.82, 95% CI ¼ 0.27-2.49,p ¼ 0.72).►Figure 4 shows a forest plot comparing the SDH and ICH groups.The results show no significant difference between the mortality rate of decerebrate patients with SDH compared with ICH (pooled OR ¼ 2.63, 95% CI ¼ 0.77-9.00,p ¼ 0.12).

Funnel plot
The included studies showed low heterogeneity in overall mortality rates (I 2 < 50%, p >0.1).Therefore, the pooled ORs were calculated using a fixed-effect model analysis.A symmetry funnel plot of the included studies in all three models showed no publication bias (►Figure 5).

DISCUSSION
The AMP is a typical feature of severe head and brain injury and could be associated with the features of raised intracranial pressure and seizure recurrence. 34A high mortality rate has been observed among AMP subjects with brain injury could raise the bar in treating the patients, whether or not they should be treated aggressively at an early stage. 20,35An early prediction of survival and efficient outcomes is important for the physician to take appropriate and aggressive treatment.In this systematic review, we have analyzed the risk factors as the mortality and morbidity prediction and posturing outcome among severe head and brain injury subjects.
Most of the decerebrate patients followed by cranial trauma have survived and recovered from a decerebrate state in a reasonably functional state, which could be due to the evacuation of an intracranial hemorrhage. 14,15,17,25,28In most survivors, the lack of serious neurological sequelae established the reversibility of brain stem compression.
The GCS score of 4 is considered a poor prognostic factor as an outcome of patients with a severe blunt head injury.72% of mortality and 16% of worthy outcomes were noticed in the decerebrate patients. 20Mahapatra et al. 1985 reported that 68% mortality and 18% recovery 26 had been noticed.Survival and recovery are based on the type of intracranial hematoma and the decerebrate state of the patients.Patients with EDH have a higher survival rate than SDH and ICH.The survival rate among subjects with cerebral contusions was poor but less than those with SDH.This has been well noticed in the reports 15,17,25,28,35,36 and is certainly related to the statement that patients with acute subdural and intracerebral hematomas have associated severe brain damage.
Age is the significant risk factor for survival after suffering traumatic decerebration.Scarcella et al. 14 reported that the recovery rate was less among subjects over 60 years compared with those under 60 years old.However, the cost and the management also play a vital role in survival among the patients after a severe head injury, as highlighted in many reports. 19,30,37here were only two studies were selected for the risk of bias test as the other studies were mostly on case report study designs.Thus only two studies 5,32 were given an  TBI and abnormal posture Wei et al.     overall score of low which was determined by consensus agreement between the two co-authors and no other clear evidence for biases was found.The effectiveness of medical treatment depends on the extent and the severity of the brain injury, the prognosis could vary among the patients with decerebrate posturing. 34,38The recovery depends on the patients' complications, however, rehabilitation therapy could be helpful in regaining the function and improving their quality of life. 39rain injury patients with decerebrate or decorticate posture should be managed with psychological support, medications, assistive devices, and rehabilitation services.Studies have reported that infrastructural problems could increase the functional outcome and might decrease mortality, as interpreted in a study on severe head injury. 40

Limitations of the present study
There are a few limitations that need to be accounted for in this study.The outcomes of predictive factors must be made with more attention.Furthermore, the records of follow-up of patients were not carried out.In addition, a critical factor that affects the outcome of decerebrate patients is the precise duration of decerebration 18 was not studied.The decerebrate rigidity takes place at a rate of 30-70% over the progression of severe TBI, MRI findings detecting the number of lesions in diverse areas of the brain also need to be recorded to determine the correlation between decerebrate posturing and lesions of the brain.The substantial heterogeneity among the patient profiles is a hallmark characteristic of TBI, hence it must be studied and analyzed in the study design.
In conclusion, the findings of this study show that poor prognosis and management in decerebrate patients have high mortality among the patients.Lesion types, age, and the duration of decerebration are the most significant prognostic factors that determine the outcome of surgery.Understanding the pathophysiology, management, prevention, and a strategy to overcome the barriers and knowledge gaps in treating brain injury patients with care is much needed to reduce the mortality rate.
TBI and abnormal posture Wei et al.3are not eligible to do the risk of bias due to the lack of information and case report studies.

Figure 1
Figure 1 Prisma flow chart of the selected studies.

TBI and abnormal posture Wei et al. 7 Figure 3
Figure 3 Forest plot of the odds ratio for mortality between decerebrate patients with EDH and ICH.

Figure 2
Figure 2 Forest plot of the odds ratio for mortality between decerebrate patients with EDH and SDH.

Figure 4
Figure 4 Forest plot of the odds ratio for mortality between decerebrate patients with SDH and ICH.

Figure 5
Figure 5 Funnel plot for publication bias of studies included in meta-analysis of mortality rates (A) between decerebrate patients with EDH and SDH, (B) between decerebrate patients with EDH and ICH and (C) between decerebrate patients with SDH and ICH.